Baltimoreed11754 Posted April 29, 2019 Report Share Posted April 29, 2019 (edited) Yesterday I cleaned my Saturdays cas/ BAM match .30-06 brass and .45 brass that I had shot in my 1927a1 WH and in my .45 AR pistol. I noticed that the Thompson fired primers were unlike any that I have seen before. Im wondering if these primers are normal for these guns? My load is what Ive used for years 4.5 gr of Red Dot under a 200 gr cast or pc bullet. Here is a photo of them compared to normal primers. All of these are the same load and bullet. Edited April 29, 2019 by Baltimoreed11754 Link to comment Share on other sites More sharing options...
Oldtrooper Posted April 29, 2019 Report Share Posted April 29, 2019 This is caused by over pressure ... Could be too hot a load or head space ... I'd try some factory loads to compare Link to comment Share on other sites More sharing options...
peter kohler Posted April 29, 2019 Report Share Posted April 29, 2019 I actually just went through this with a 27 I changed the firing pin and it completely eliminated the problem mine was piercing the primers. make sure you do some research on here about replacing the pin and filing it to fit not a difficult thing to do. Link to comment Share on other sites More sharing options...
wh20crazy Posted May 21, 2019 Report Share Posted May 21, 2019 I got the same intentions on my WH. The replacement fitting pin fixed it. If you look at the bolt face, you'll see the slot that causes this. It's not over pressure. I got it with factory loads and my reloads, which are bottom of the scale (7.1 grains of Accurate #5 under a 230 grain plated ball). Worst part is sometimes the primer will come out of the case and cause a jam. May be getting some gas escaping to the rear when that happens too. Link to comment Share on other sites More sharing options...
ppgcowboy Posted May 21, 2019 Report Share Posted May 21, 2019 When you say you have been using that recipe for years, would that be in a pistol with a 4 inch barrel? Link to comment Share on other sites More sharing options...
Baltimoreed11754 Posted May 24, 2019 Author Report Share Posted May 24, 2019 Yes sir, it works my in Detonics, Colt New Agent, blowback Olympic Arms carbines and full size 1911s. I use the same bullet [not the same powder] in my cowboy .45lc Vaquero revolvers. Link to comment Share on other sites More sharing options...
ppgcowboy Posted May 24, 2019 Report Share Posted May 24, 2019 Do you have a chronograph? If you do,look for around 950fps. I think at times that people load for pistols and putting them in rifles do not aklways match up well. Just me thinking. Link to comment Share on other sites More sharing options...
TSMGguy Posted May 25, 2019 Report Share Posted May 25, 2019 Overpressure will normally cause the soft primer to fill the entire primer pocket, even the chamfer. If this round is overpressure, it isn't by much. Link to comment Share on other sites More sharing options...
Baltimoreed11754 Posted July 28, 2019 Author Report Share Posted July 28, 2019 I carried my 1927 a1 WH to my cas match yesterday to show off and let one of the cowboys try it out. Well I just finished cleaning my brass from the match .45 lc [Marlin 1894], .38-40 [Colt New Service revolvers] and the .45 acp that he shot. Lo and behold I don't have the aforementioned deformation on these primers, they look normal. Same load except for the round nose bullet. The only difference in the gun is the install of shortened McMaster Carr springs and a buffer. Don’t understand but normal primer indentations are ok by me. My 10.5 bbl arrived from GPC, waiting on my sbr paperwork. It’s been five months 17 days so far. Link to comment Share on other sites More sharing options...
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